The invention relates to a bearing for the spinning rotor of an open-end spinning assembly or the like, whose shaft is supported axially with its end against a ball wet with lubricant, said ball being mounted in a step bearing housing and held against a guide surface in such manner that it can be excited to vibrate.
In a known design of the type described hereinabove (German Auslegschrift No. 23 17 306), a spring-like elastic element serves as a retainer for the ball, said element being disposed in the step bearing housing and supporting the ball directly. The machine vibration causes the ball to move within narrow limits relative to the end of the rotor shaft and also relative to its guide, so that the ball can no longer be held firmly after a prolonged period of operation. The known design produces good results in practice, i.e., low wear. However, there is the danger that in the event of rough treatment or overloading of the spinning rotor resulting from jamming of the latter, the spring-like element will be overloaded and possibly deformed.
An object of the invention is to provide a maximally compact and stable bearing of the type described hereinabove, capable of withstanding rough treatment and overloads and nevertheless making it possible for the ball to move relative to the rotor shaft as a result of the vibrations thereby avoiding jamming. This object is achieved by virtue of the provision that the step bearing housing, provided as a support for the ball, is held by a component of the spinning assembly which is excitable to vibration.
The invention is based, at least in part, on the discovery that it is not absolutely necessary to excite to vibration the part against which the ball rests directly, but rather that the entire step bearing can move in the form of vibrations, since this also results in the relative movement between the ball and the rotor shaft. Movements of this kind resulting from vibration also result in a situation in which the ball moves relative to its holder and its support point changes, so that it can be caused to make rotary movements without difficulty.
In an advantageous embodiment of the invention, provision is made for the step bearing housing to be provided with at least one bracket, said bracket being mounted on a pillow block which accepts a radial bearing supporting the spinning turbine shaft. A bracket of this kind is caused to vibrate, since it was discovered that vibrations cannot be avoided within the radial bearing which are then transmitted to the bracket in the type assemblies contemplated.
In another embodiment of the invention, provision is made for the step bearing housing to be mounted on one wall of a machine frame. In practice, it was discovered as unavoidable for a wall of this kind to be excited to membrane-like oscillations when the machine is operating, when this motion can be used in turn to move the ball relative to the rotor shaft.
In yet another embodiment of the invention, provision is made for a ball retainer provided with a calotte or cup-shaped shell, to which retainer a cage surrounding the ball is fastened. These parts can all easily be made quite strong, since they themselves need not be excited to vibration. This makes it possible to make the ball retainer and/or an insert forming the calotte from a porous sintered material. A material of this kind makes it possible to provide additional lubrication for the ball.
In yet another embodiment of the invention, provision is made for the ball retainer to be in the form of a lever with one end swivelable and lockable with respect to a pin. This makes it possible to ensure a very precise axial alignment of the ball and hence the rotor shaft. Provision can also be made according to contemplated preferred embodiments for the free end of the lever to be brought preferably upward and outward from the step bearing housing and be provided with a locking device. This arrangement makes it possible to perform axial adjustments without opening the step bearing housing.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.